Volatile anaesthetic vaporising apparatus



Sept. 3, 1968 w JONES ETAL 3,399,673

VOLATILE ANAESTHETIC VAPORISING APPARATUS Filed June :2, 1965 al/m o-ndocm A, aw,x5(1,,gw- Pin/ ABSTRACT OF THE DISCLOSURE ,A portable anaesthetic apparatus comprises a valvecontrollable volatile anaesthetic vaporiser having a connection from its inlet to a high region outlet from an oxygen economiser reservoir furnished with a high region air inlet-exhaust port, a pendant partly dividing plate in said reservoir between said inlet and said outlet, an oxygen supply inlet to the connection between the vaporiser and the reservoir, 2. connection between the outlet from said vaporiser and a flow control valve unit, twin vertically spaced-apart light-weight plate valve members controlling two flow passage ports leading to a connection to a face mask, a third inlet port between said two ports with an inlet connection from a bellows unit, and a passage from the bellows inlet connection to a pressure chamber in said valve unit behind a diaphragm, said diaphragm controlling a valve which normally closes an expiration port from the face mask to atmosphere.

This invention relates to apparatus capable of mixing the vapour of a volatile liquid anaesthetic with a gaseous fluid, such as air or oxygen, or a combination thereof.

There are occasions when a portable anaesthetic apparatus could be an advantage for the administration of a volatile anaesthetic in air to which oxygen could be added economically. Such an apparatus may be of a type to be used almost anywhere an operation could be carried out and thus it would be ideal for emergency work. Said apparatus could be such that it would not include an oxygen cylinder, as such cylinders may be available on the site of an accident, although an oxygen cylinder could be included and'the unit be more of a transportable type.

According to the present invention there is provided anaesthetic apparatus, including a valve controlled volatile anaesthetic vaporiser, a reservoir providing an air inlet to the vaporiser, oxygen supply means connected to the vaporiser and reservoir, a valve control unit connected to said vaporiser and a bellows unit and controlling an inspiration outlet to and an expiration outlet from connection means for a patients mask, said unit having nonreturn valve means between said inspiration outlet the bellows unit and the vaporiser for controlling the flow of air/oxygen and anaesthetic vapour mixture and a patients expiration.

The invention will now be more particularly described with reference to the diagrammatic view in the accompanying drawing.

According to the drawing the improved apparatus, which may be constructed to be portable or otherwise, includes a liquid anaesthetic containing vaporising unit 1 for air and/or oxygen to pass thereinto and become admixed with a percentage of anaesthetic vapour according to a predetermined setting of the unit. This vaporising unit is preferably of a nonspillable type, such as is disclosed in our prior British Patent Specification No. 968,- 054, dated Feb. 4, 1963, where there is an inlet 2 and an outlet 3 on opposite sides of the unit for a through flow of air and/ or oxygen and a rotatable plate valve 4,

which normally closes an inlet 5 to and an outlet 6 from a vaporising chamber 7 or chambers. The latter also includes a valve 8 carried by a temperature responsive element 9 and this valve or another valve controls the outflow of anaesthetic vapour. When the plate valve 4 is turned it initially opens the aforesaid inlet to and outlet from the vaporising chamber or chambers. The said plate valve has an upstanding rib 10 which is rotated in relation to superposed inclined facings 11 which causes the through passage for air and/ or oxygen to be variable.

The vaporising unit 1 is connected to an oxygen economiser receptacle 12 which has a pendant partly dividing plate 13 between an air inlet 14 (which may be controllable) and an outlet 15 connected by pipe 16 to the inlet to the vaporiser unit. An inlet 17 for oxygen is linked to the said connection pipe 16 and a flow meter 18 is provided to give visible indication of the inlet of oxygen from a supply source. This inflow of oxygen is controlled by a fine control valve 19 and a feed pipe 20 is provided for connection to a cylinder and fitted with an oxygen reducing valve.

The vaporiser unit 1 is connected by pipe 21 from its outlet 3 to a connection unit 22 embodying a direction flap valve 23 for controlling the inflow of air-oxygenanaesthetic-vapour through an inlet port 24 with a further inlet port 25 spaced away therefrom and controlled by a nonreturn flap valve 26. The two valves are thin plates or discs resting by gravity on the port seatings to be raised by a patients inspiration or bellows induced pressure. Stop means 23a and 26a restrict the opening movements of the valves. Between these two valves there is a third port 27 connected to a manually operated bel lows unit 28. From this connection unit there is. an outlet 29 to which can be attached a flexible connection tube 30 to a facepiece 31 which has a second flexible tube 32 also connected to the said connection unit at an inlet 33. The two flexible tubes are conveniently connected to the facepiece by a Y-coupling 34. The unit 22 has a passageway 35 leading from the second flexible tube inlet 33 to a port 36 normally closed by an expiratory valve 37 over which there is mounted a spring returned plunger 38 connected to a flexible diaphragm 39. A passage 40 leads from a chamber 41 above the diaphragm to the connection 42 between the said unit 22 and the bellows 28 and there is an expiratory port 43 in the wall of the connection unit from the region where the expiratory valve mounted.

With the above type of apparatus a patient can have normal breathing and draw in air and/0r oxygen, or anaesthetic vapour mixed with air and/or oxygen. Expiration can take place normally through the second flexible tume 32 to the expiratory port 43 by expired air pressure opening the expiratory valve 37. Should it be necessary, breathing can be assisted by operation of the bellows unit 28. It will be appreciated that as a patient inspires air can be drawn through the oxygen economiser 12, through the vaporiser unit 1 and the two nonreturn spaced apart valves 23, 26, and thence through the first flexible tube 30 to the facepiece 31. As the patient expires the second nonreturn valve 26 will close and thus all expiration will pass out through the aforesaid valve 37 to the expiratory port 43. If it is desired to supplement the air with oxygen the fine control valve 19 is opened to admit oxygen from a supply source at a desired rate. By providing an economising unit 12, while a patient is expiring or not breathing, the oxygen flow Will be charging the economiser unit itself, and this will discharge any existing air in the economiser through the air inlet 14. Thus as the patient next inspires he will firstly draw in pure oxygen from the economiser and then air or an admixture of air and oxygen. The percentage of oxygen received by the patient will be dependent on the rate of flow of oxygen according to the setting of its inlet control valve 19 and the patients minute volume. By the expression minute volume is meant lung capacity per one minute. It will be understood that the percentage of oxygen a patient receives will vary according to the patients own minute volume which of course differs with different patients.

If it is necessary to assist a patients breathing then the bellows 28 can be operated and this will draw air and/ or oxygen and/or vaporised anaesthetic into it and then cause it to be forced through the second of the nonreturn valves 26 and the first flexible tube 30 to the facepiece 31. The said second nonreturn valve 26 prevents any air being drawn from the patients lung. Operation of the bellows which causes the pressure in a patients lungs to be raised causes a pressure to be transmitted to the aforesaid chamber 41 in the connection unit 22 behind the flexible diaphragm 39. Pressure on the diaphragm causes the plunger 38 to be forced down on to the expiratory valve 37 to hold it closed against any escape to atmosphere during the period when there is ejection into the patients lungs. As the bellows are expanded pressure on the said diaphragm will be immediately released to release the expiratory valve and thus allow passive expiration to atmosphere from the patients lungs.

It will be understood that during spontaneous breathing there will be some movement of the bellows which will give some indication of the patients breathing. On the other hand, a more precise measurement of tidal volume may be obtained by fitting a respirometer to the air inlet to the economiser unit, although this will not give entirely accurate indication under all conditions.

The above apparatus may be mounted on a base plate which may have gripping means and rubber feet. A carrier case may be provided. Alternatively, the apparatus may be on a trolley or be otherwise movable. The vaporising unit may be of the nonspillable type and include a drainage outlet.

It is considered the invention provides at least two important features, i.e., automatic loading and unloading of the expiratory valve by the bellows created pressure, and economy in or full benefit of pure oxygen provided in the system through the fiowmeter.

We claim:

1. A portable anaesthetic apparatus, including in combination:

a valve-controllable volatile anaesthetic vaporiser having an inlet and an outlet;

an oxygen economiser reservoir having a high region air inlet-exhaust port and a high region outlet;

a connection from said vaporiser inlet to said high region outlet of said reservoir;

a pendant partly dividing plate in said reservoir between said inlet and said outlet;

an oxygen supply inlet to the connection between the vaporiser and the reservoir;

:a flow control valve unit having two sequential flow passage ports;

a connection between the outlet from said vaporiser and said flow control valve unit;

a face mask;

twin vertically spaced-apart lightweight plate valve members controlling said two flow passage ports in said valve control unit and leading to said face mask;

a bellows unit;

a third inlet port in said valve control unit between said two sequential flow passage ports, said third inlet port having an inlet connection from said bellows unit;

a diaphragm in said valve control unit;

a pressure chamber in said control valve unit behind said diaphragm;

a passage from said bellow-s inlet connection to said pressure chamber;

an expiration port leading from said face mask to atmosphere; and

an expiration valve which normally closes said expiration port, said diaphragm controlling said expiration valve.

2. Anaesthetic apparatus according to claim 1, wherein the valve members are gravity closed flap valves resting on said ports with stop means to restrict their opening movements.

3. Anaesthetic apparatus according to claim 1, wherein said valve control unit includes two tubular connection elements, one of said elements being an outlet for valve controlled air/oxygen and anaesthetic vapour and the other element leading to said valve controlled expiration port, and a pair of flexible tubes adapted to be removably attached to said connection elements, said tubes being joined together at their other ends and to a patients face mask.

References Cited UNITED STATES PATENTS 2,572,199 10/1951 Richards 128-l86 X 3,107,689 10/1963 Schreiber et a1. 128-188 X 3,126,001 3/1964 Engstriim 128-488 X 3,128,764 4/1964 Koehn l28-188 3,162,192 12/1964 Gardner et al. 128188 RICHARD A. GAUDET, Primary Examiner.

W. E. KAMM, Assistant Examiner. 

